The candidate for this Scientist Development Award for Clinicians will obtain a comprehensive understanding about and research skills related to the putative risk factors in the development of obesity in infants and children. The candidate will receive a broad, but in depth review of the genetic, psychological, nutritional and metabolic issues related to the development of obesity. A focus will be in the area of chemosensory stimulation of ingestive behavior, hunger, and satiety. The area of energy expenditure will be fully explored as it relates to the development of obesity and ingestive behavior. The candidate will develop skills in research methods in these areas, using the proposed Infant Growth Study as a practice exercise and as a scientific exploration of these issues. The candidate will participate in a prospective study assessing, singly and interactively, the predictive value for adiposity of the proposed five factors: 1) maternal obesity, 2) infant sucking style, 3) food intake, 4) total energy expenditure, and 5) resting energy expenditure. The Infant Growth Study is a prospective examination of infants at high risk (born of obese mothers) for obesity and infants at low risk (born of lean mothers). In previous studies, a vigorous infant sucking style with high pressure sucking, increased caloric consumption for the first year of life, and low energy expenditure levels predicted excess adiposity at one year. In the Infant Growth Study, all factors will be evaluated prospectively in the same study and the candidate will participate in all phases of assessment. Multiple measures of infant sucking behavior, food intake, energy expenditure and body composition will allow for tests of interactions of the variables. Adiposity assessments through 4 years of life will allow for longer analysis of the predictiveness of these variables.